This invention describes an imaginative new footwear design based on the principle of energy conversion. The inventive footwear will make walking and running smoother, easier, more efficient, quicker, and simultaneously will reduce injuries arising from impact forces.
All walkers and runners fit in two simple categories, those who land on their heels and those who land on their toes. Although the term xe2x80x9crunnerxe2x80x9d is used throughout the specification, it is noted that the term xe2x80x9crunnerxe2x80x9d could also be a person walking and not running (xe2x80x9cwalkerxe2x80x9d).
Heel runners: These, known also as xe2x80x9cheel strikersxe2x80x9d, land on the back portion of their heel, roll forward on the outer side of the foot, and push off from the toe-forefoot area. The xe2x80x9cstrikingxe2x80x9d occurs in a relatively small region at the rear and outside of the heel. The impact of force or pressure of landing is calculated in pounds per square inch. That is, the weight of the runner multiplied by the impact area in square inches (small; say one half by one inch). The resulting impact pressure or force is large, often awesome. Since the descent of the foot on hitting the ground stops abruptly, in fact almost instantaneously, the law of xe2x80x9cequal opposite forcesxe2x80x9d dictates that an equal pressure or force is transmitted in the opposite direction, back up the leg from foot to ankle to knee to hip. Taken over time, this jolt in distance runners (30 miles or more a week) causes predictable wear and tear problems involving foot, ankle, knee, hip and even back. This is the source of most injuries in distance runners. In addition, most xe2x80x9cheel strikersxe2x80x9d land with center of gravity slightly behind the point of impact, hence some of the reactive force up the leg actually pushes them backward. The runner locks the knee and xe2x80x9cpogo-sticksxe2x80x9d over the foot before rolling forward to the push-off position. This is inefficient, wasteful of energy, and tiring while causing a small though real slowing of the runner""s forward progress.
Toe Runners: The other, smaller group of runners land on their toes or actually their forefoot areas. The point of impact is more apt to be under or modestly behind their center of gravity. The knee is slightly bent and absorbs some reactive energy. This style propels the runner forward, is more efficient, less tiring, and less prone to injuries. This group tends to be the sprinters and the elite distance runners.
All shoes are basically the same. Tops to cover the foot and keep the bottoms in place. Bottoms to protect the sole and to provide cushioning to absorb impact pressures.
Over recent years, shoe manufacturers have developed a variety of materials to reduce impact pressures through principles of compression and dispersion to absorb energy. Thus, modifications in design and composition of the heels (sponges, inserts, treads, air, and gels) and forefoot (sponges, inserts, and treads). All shoes employ the same principles with only a variation in theme. Thus the following:
U.S. Pat. No. 4,616,335 describes an athletic shoe structure including shock absorbing portions in the heel and foot areas of the sole of the shoe as well as particular placement of flexible nubs on the soft area.
U.S. Pat. No. 4,348,821 is directed towards the development of a shoe sole construction that will be mechanically effective for walking, running or jogging.
U.S. Pat. No. 4,262,435 is directed to an improved athletic shoe and with the sole piece as a wedge to facilitate supporting the runner""s foot when contacting the ground.
U.S. Pat. No. 4,614,046 issued to Dassler (xe2x80x9cDasslerxe2x80x9d) describes a shoe which has two low points and not a single low point (FIG. 5 of Dassler). One low point is in the middle to the front of the shoe and the other low point is in the middle to the back of the shoe. There is not a single low point as is preferred by one of the embodiments the inventive shoe. Therefore, the shoe of Dassler would not roll smoothly forward converting energy into useful forward motion while reducing reactive impact force that normally travels back to the leg. There is no suggestion nor teaching in Dassler to have a single low point which would enable the runner to convert this negative energy into positive energy.
U.S. Pat. No. 4,372,059 issued to Ambrose (xe2x80x9cAmbrosexe2x80x9d) discloses a shoe with a single low point (at the line 4xe2x80x944) in about the center of the sole. The problem that arises with this location of the single low point is that when the heel striker""s shoe makes contact with the ground surface at the back end of the shoe, the shoe will try to roll forward, but in reality, will apply a force that may either cause the shoe to roll backwards or cause the user to force the shoe to roll forward being less efficient and generally increasing the possibility of injury to the user. One embodiment of the inventive shoe would provide that when the user lands on the ground surface on the back rear section of the sole of said shoe, the sole would then roll from the rear section to the front section of the shoe smoothly, thereby reducing reactive impact force.
Today, there is a need to make the shoe better by incorporating the concept of xe2x80x9cconversionxe2x80x9d in the design of the shoe. There is no shoe to date that employs the principle of energy conversion.
This invention focuses on energy conversion as a new concept in running shoes. Secondarily it describes a new configuration for the treads and a new, replaceable shock absorber unit. Both are a direct consequence of the basic innovated shoe design.
An object of this invention is the design and development of the shoe with a rounded heel strike area and gently curved bottom. The user, such as a walker or runner, while engaging in movement would have the shoe make contact with the ground surface and the shoe would roll smoothly forward converting energy in a useful forward motion while reducing the reactive impact force that normally travels back up the leg. The runner would thus be more efficient with simultaneous decrease in injuries due to impact pressures.
The term shoe is used throughout the specification and in some figures specific shoes are mentioned. However, it is to be understood that the term xe2x80x9cshoexe2x80x9d includes running shoes, walking shoes, slippers, sandals, thongs and boots.
Another object of this invention is the design and development of modified treads. Since most heel strikers slide or shuffle rather than plant their foot in making first contact to the ground, the treads on the heel and back portion of the shoe should embrace or utilize this fact by making the treads a series of longitudinal grooves much like the grooving of an automobile or airplane tire. In contrast, the forefoot treads should be horizontal grooves or ridges to facilitate the force or gripping of the ground in the push-off of running.
Another object of this invention is the design development of the replaceable shock absorber unit to nestle within the rounded, thickened heel.
Another object of this invention is the design of the shoe that will enable a heel striker to land on the rear section of the sole behind the ankle. When the runner is walking or running, the runner""s shoe would land in front of the runner""s center of gravity. The sole of the shoe could have a single low point located backwardly of the ankle. When the shoe is resting on a horizontal flat ground surface the front of the shoe can be elevated such that the inner sole would be parallel to the ground surface.
Taking these three components separately and together, this invention will create a shoe to enhance ease, comfort, smoothness, and efficiency while allowing a greater longevity of the product and reducing running injuries.
This invention is directed to a shoe for a human foot comprising a sole piece and an upper piece. The sole piece consists essentially of a front, middle, and rear section with a ground engaging bottom surface. Further, the sole piece will be curved, particularly at the rear permitting the users foot to tilt slightly forward to enhance power during the push-off phase of the stride. The upper piece, secured to the bottom, creates an enclosure to embrace the foot. The upper piece can partially or fully enclose the shoe. If the upper piece fully encloses the shoe it too would have a front or toe box section, a middle and a rear section.